This invention relates to wind engines and in particular to a wind driven pumping apparatus, but it will be appreciated that the application of the engine need not be restricted to pumping water from boreholes which is the application described in the specification.
The invention is intended to exploit the fact that, because gas is compressible the energy therein can be stored and released in a controlled manner. This is of particular significance for wind-energised apparatus since, as is commonly known, there is a considerable and continuous variation in the strength at which the wind blows. Conventional windmills do not utilise fully the upper and lower scales of wind speeds, they suffer from the defect that furling and braking means must be provided for the windmill to stop due to risk of damage thereto, when the wind blows too hard. At low wind speeds the windmill does not work efficiently owing to the often large starting resistance applied to the wind wheel by gear trains and the mass of the water required to be lifted from the well.
It is an object of this invention to provide a windmill that is capable of overcoming this problem.